Mesenchymal stem cells are present in mammalian marrows etc. and known as pluripotential stem cells, which can differentiate into adipose cells, cartilage cells, and bone cells. Due to its pluripotency, mesenchymal stem cells are highly expected as transplantation material for use in regenerative medicine for many kinds of tissues. That is, the use of mesenchymal stem cell enables “regenerative medicine by cell transplantation” for regenerating lost tissues lost due to diseases or impairment and have not been able to be regenerated by a conventional remedy method. More specifically, therapeutic treatments have been started or planed, which are for example, transplantation of marrow mesenchymal stem cells to a patient of lower limb ischemia (Buerger's disease), transplantation of marrow mesenchymal stem cells to a patient of a periodontal disease, transplantation of marrow mesenchymal stem cells to a patient of osteoarthritis, transportation of amniotic epithelium sheet to burn injured portion, transportation of amniotic stem cells to a patient of diabetes mellitus, and the other transplantation.
In order to use mesenchymal stem cells for regenerative medicine, the stem cells should be collected from a living tissue and then multiplied without differentiation, and the multiplied and undifferentiated stem cells should be induced to differentiate to desired cells in order to prepare tissue for the regenerative medicine.
The inventors of the present invention have reported a method of easily collecting mesenchymal stem cells by separating mesenchymal stem cells from an oral cavity tissue, which method is safe for an individual from which the mesenchymal stem cells are collected (see Patent Citation 1). Moreover, the inventors of the present invention have reported a culturing method, which can give a significantly larger amount of mesenchymal stem cells than can a conventional culturing method. The culturing method having been reported by the inventors of the present invention is based on a fact found by the inventors that mesenchymal stem cells can be multiplied at a dramatically fast rate by culturing the mesenchymal stem cells in the presence of an extracellular matrix of a basement membrane or in a medium containing fibroblast growth factor (FGF) etc. and this culturing method can multiply mesenchymal stem cells without the differentiating ability thereof (see Patent Citation 2).
These arts are not enough to make the regenerative medicine using the mesenchymal stem cells practically applicable. To speak specifically, for the preparation of the tissue for regenerative medicine by inducing the differentiation of the cultured and multiplied mesenchymal stem cells to desired cells, the cultured cells should be confirmed beforehand that they are mesenchymal stem cells. That is, it is necessary to develop a method of detecting and distinguishing the mesenchymal stem cells after the culturing and multiplication.
To solve this technical problem, the inventors of the present invention have developed a method of effectively identifying and separating mesenchymal stem cells and fibroblast, which are morphologically similar and thus difficult to be distinguish, the method using a gene maker and/or a protein marker for detecting mesenchymal stem cells (see Patent Citation 3).
[Patent Citation 1]
Japanese Patent Application Publication, Tokukai, No. 2003-52365 (published on Feb. 25, 2003).
[Patent Citation 2]
Japanese Patent Application Publication, Tokukai, No. 2003-52360 (published on Feb. 25, 2003).
[Patent Citation 3]
Japanese Patent Application Publication, Tokukai, No. 2005-27579 (published on Feb. 3, 2005).